Core Training Balls are important tools used in many Pilates exercises. They can be used to help keep alignment, and are a key tool to help strengthen the abdominal core in mat classes. Their unique shape allows clients to easily hold, balance, or place them anywhere they need extra help. Provide them to your Pilates clients to add extra stability or resistance to their practice! Each sold separately. All core training balls come un-inflated with a blow tube to properly inflate. You may also use a pump.